Inheritance — IGCSE Sciences - Co-Ordinated (0973) questions by topic
Inheritance questions trace cystic fibrosis through a pedigree diagram, work out chromosome numbers in donkey-and-horse hybrid gametes, define inheritance, and identify a heterozygous genotype from four descriptions, worth from 1 to 10 marks in this IGCSE Co-ordinated Sciences set.
State, identify and complete top the command words, with calculate and deduce also frequent: deduce a genotype from a pedigree diagram using the given recessive and dominant alleles precisely. 11 real questions from 2023 to 2025 papers make up this page. Submit each attempt for instant marking so a recessive allele mistakenly read as dominant is caught immediately.
May–June 2025, Paper 21
Polydactyly is the possession of additional fingers or toes. It is caused by a dominant allele. The pedigree diagram shows the inheritance of polydactyly by a family. The key…
Answer this question and get it marked →May–June 2025, Paper 22
Some information about a donkey and a horse is shown. - The sperm from a donkey is able to fertilise the egg from a horse. - The nucleus of a body cell from a horse has 64…
Answer this question and get it marked →May–June 2024, Paper 12
Which statement describes a heterozygous genotype? A not pure breeding with two different alleles B not pure breeding with two identical alleles C pure breeding with two different…
Answer this question and get it marked →May–June 2024, Paper 21
The diagram shows the inheritance of a disease (key: unaffected/affected males and females). Two unaffected parents have an affected child. [Pedigree diagram: unaffected parents…
Answer this question and get it marked →May–June 2024, Paper 22
Which row about the nucleus of human cells is correct? A diploid, 23 chromosomes, gamete B diploid, 46 chromosomes, body cell C haploid, 23 chromosomes, body cell D haploid, 46…
Answer this question and get it marked →October–November 2024, Paper 31
May–June 2023, Paper 11
The diagram shows eggs and sperm containing sex chromosomes. Eggs: 1 = XX, 2 = X, 3 = XY, 4 = Y. Sperm: 5 = X, 6 = Y, 7 = XX, 8 = XY. Which row gives the correct combination of…
Answer this question and get it marked →May–June 2023, Paper 21
The diagram shows eggs and sperm containing sex chromosomes. Eggs: 1 = XX, 2 = X, 3 = XY, 4 = Y. Sperm: 5 = X, 6 = Y, 7 = XX, 8 = XY. Which row gives the correct combination of…
Answer this question and get it marked →May–June 2023, Paper 42
Fig. 10.1 is a diagram of a sperm cell in humans, with cell structure X (the head/nucleus) and part Y (the midpiece) labelled. Cell structure X contains unpaired chromosomes.…
Answer this question and get it marked →October–November 2023, Paper 21
Cats with polydactyly have an extra digit on their paw. The allele for polydactyly, P, is dominant to the allele for having five digits, p. The pedigree diagram shows a family of…
Answer this question and get it marked →October–November 2023, Paper 41
Fig. 1.1 is a pedigree diagram for the inheritance of cystic fibrosis. The allele for cystic fibrosis is recessive (a); the allele for no cystic fibrosis is dominant (A). Two…
Answer this question and get it marked →Other IGCSE Sciences - Co-Ordinated topics
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